Setting of rotation time
It is necessary to calculate the inertial load and kinetic energy in the application prior to setting the speed
of the actuator. The inertial load generated in the application may be high even if the torque required in the
application is low, this may lead to damage to the internal components of the actuator.
Moment of inertia
The moment of inertia indicates how hard it is to rotate an object, and also how hard it is to stop the object
once it is rotating.
Any object rotated by a rotary table will have an inertial force.
When the rotary table stops at the stroke end, the actuator will receive a big impact (kinetic energy) due to
the inertial force.
Please refer below for calculation of kinetic energy.
2
2
1
I
E
E: Kinetic energy [
J
]
I: Moment of inertia [
2
m
kg
]
ω: Angular speed [
s
rad
]
Allowable kinetic energy for the rotary actuator is limited. The limit of rotation time is obtained by calculating
the moment of inertia.
Please refer below to calculate the moment of inertia.
Basic moment of inertia
2
r
m
I
m
: Weight
[ kg ]
r : Center of gravity of load and distance of rotational axis [ m ]
This shows moment of inertia of
“m (weight)” at “r” distance from the axis of rotation.
The calculation for the moment of inertia depends on the shape of the object.
Please refer the table on the next page for the moment of inertia calculations.
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Fig. 6
2020-10-13 10:38
DI987004
